Esters of oxypropylated polypentaerythritols



Patented May 25, 1954 I 2,679,516 OFFICE ESTERS OF OXYPR PENTAERY OPYLATED POLY- THRITOLS Melvin De Groote, University City, Mo., assignor to Petrolite Corporation, a corporation of Delaware No Drawing. Application May 14, 1951, Serial No. 226,315

8 Claims. 1

The present invention is a; continuation-inpart of my copending applications, Serial Nos. 127,773, now U. S. Patent No. 2,552,533, and 127,774, now abandoned, both filed November 16, 1949. Said aforementioned co-pending applications represent in turn a continuation-in-part of my co-pending applications, Serial Nos. 104,801, now U. S Patent No. 2,552,528, and 104,802, now abandoned, both filed July 14, 1949. See also my co-pending applications, Serial Nos. 104,805, now U. S. Patent No. 2,554,667, and 104,806, now abandoned, both filed July 14, 1949.

The present invention is concerned with certain new chemical products, compounds, or compositions which have useful application in various be free from any radical having at least 8 uninterrupted carbon atoms; (b) the initial polyhydric reactant have a molecular weight not over 1,200 and at least 4 hydroxyl radicals; initial polyhydric reactant be water-soluble and xylene-insoluble; (d) the oxypropylation end product be Water-insoluble and Xylene-soluble;

respect to Water and xylene be substantially the result of the oxypropyla'tion step; (9) the ratio of propylene oxide per hydroxyl in the initial 70; (h) the initial polyhydric reactant represent not more than propylation end product on a statistical basis,

complete reaction involving the propylene oxide and the initial poiyhydric reactant.

Claim 1 of Serial No. 104,802, filed July 14, 1939, now abandoned, is substantially the same, except that it is concerned with the high molal 2 oxypropylation derivatives as such and not specifically for demulsification.

Attention is additionally directed to the copending application of Melvin De Groote, Serial No. 127,771, now S. Patent No. 2,552,532 filed November 16, 1949. Briefly stated, the particular invention described in this co-pending application is concerned with the breaking of basis step; (i) the initial polyhydric reactant represent not more than 7% by weight of the oxypropylation end product on a statistical basis, and that scribed inventions in that the initial reactant is not water-soluble, thus being distinguished from the inventions in my co-pending applicaleast colloidally water-soluble. Stated another way, in the said invention the initially water-insoluble and Xylene-insolube material is treated at once with propylene oxide so as to render it xylene-soluble.

The final oxypropylation products as described in co-pending application Serial No. 127,773, now U. S. Patent No. 2,552,533, are not only Xylenesoluble but may be even water-dispersible, especially in the latter stages of oxypropylation. In the higher stages they are invariably water-insoluble and this applies particularly to the oxypropylation derivatives derived from polypentaerythritol of a molecular weight greater than that of hepta-pentaerythritol.

More specifically, then, the process of Serial No. 127,773 is concerned with treating petroleum emulsions of the water-in-oil type with the oxypropylation products obtained from tripentaerythritol and higher polypentaerythritols.

Similarly, co-pending application, Serial No. 127,774, now abandoned, is concerned with the compounds as such and is not specifically limited to the use as demulsifiers.

Referring to the two previously mentioned coto wit, Serial Nos. 127,773, now U. S. Patent No. 2,552,533, and 127,774, now abandoned, both filed November 16, 194:9, there appeared subject matter concerned with derivatives of such oxypropylated polyhydric compounds and which stated that such oxypropylated polyhydric compounds can be combined with a wide variety of polycarboxy acids, such as tricarballylic acid, or citric acid, but it is preferred to employ a dicarboxy acid, or acid anhydride, such as oxalic acid, maleic acid, tartaric acid, citraconic acid, phthalic acid, adipic acid, succinic acid. azelaic acid, sebacic acid, adduct acids obtained by reaction between maleic anhydride, citraconic anhydride, and butadiene, diglycollic acid or a cyclopentadiene adduct. A specific type described includes acidic fractional esters, i. e., esters having free carboxyl radicals.

Furthermore, as stated in said previously referred to subject matter, the new derivatives include among others acid esters of the kind just referred to and having the properties of the original hydroxylated compound insofar that they are effective and valuable demulsifying agents for resolution of water-in-oil emulsions as found in I the petroleum industry, as break inducers in doctor treatment of sour crude, etc.

Dipentaerythritol is only slightly water-soluble at ordinary temperatures, possibly in the neighborhood of about two-tenths per cent. It is not unusual to classify such materials for ordinary purposes as being sparingly soluble or insoluble for the particular purpose in mind. In other words, dipentaerythritol is in essence a borderline compound that can be classified either way, depending on the purpose in mind. For this rea son I have preferred to consider dipentaerythritol as water-insoluble in the present description and thus include it with tripentaerythritol and higher pentaerythritols. Such change involves essentially only one change in the description of the invention of Serial No. 127,773, now U. S. Patent No. 2,552,533, to wit, including polypentaerythritols that have at least 6 hydroxyl radicals. In essence, the only other change required is to take out the word waterinsoluble for the reason that tripentaerythritol and higher pentaerythritols are water-insoluble and the status of dipentaerythritol, as previously pointed out, has already been noted. Otherwise,

some awkward nomenclature, such as polypentaerythritols which at the most are only sparingly water-soluble would have to be included and would add nothing to point out the invention with greater specificity. This simply means that what is said herein is also a continuation-in-part of aforementioned co-pending applications, Serial Nos. 104,805, now U. S. Patent No. 2,554,667, and 104,806, now abandoned, both filed on July 14, 1949. These last two co-pending applications in essence were concerned with dipentaerythritols previously described.

In fact, there does not seem to be anything gained by including reference to having at least 6 hydroxyls for the reason that all polypentaerythritols beginning with dipentaerythritol upward have at least 6 hydroxyls. Furthermore, they are all xylene-insoluble. With this in mind, it will be noted that the statement of the invention subsequently has been simplified. As has been pointed out previously, due to commerical availability and for other reasons, my preferred polypentaerythritols are dipentaerythritols and tripentaerythritols.

The present invention is concerned with these last-mentioned previously-described acidic esters (co-pending Serial Nos. 104,805, now U. S. Patent No. 2,554,667, and 104:,806 now abandoned, both filed July 14, 1949; and Serial Nos. 127,773, now U. S. Patent No. 2,552,533, and 127,774, now abandoned, both filed November 16, 1949) as new chemical compounds and which are of particular value as demulsifiers for water-in-oil emulsions. More specifically, then, the present invention is concerned with certain acidic fractional esters; said acidic fractional esters being obtained by reaction between (A) a polycarboxy acid and (B) high molal oxypropylation derivatives of polypentaerythritols, with the proviso that (a) the initial polyhydric reactant be free from any radical having at least 8 uninterrupted carbon atoms; (b) the oxypropylation end prodnot be within the molecular weight range of 5,000 to 65,000 on an average statistical basis; (0) the oxypropylation end product by xylenesoluble; (d) the xylene solubility characteristics of the oxypropylation end product be substantially the result of the oxypropylation step; (e) the initial polyhydric reactant represent not more than 7% by weight of the oxypropylation end product on a statistical basis; and that (f) the preceding provisos be based on complete reaction involving the propylene oxide and the initial polyhydric reactant; with the proviso that the ratio of (A) to (B) be one mole of the polycarboxy acid for each available hydroxyl radical.

Although the herein described products have a number of industrial applications, they are of particular value for resolving petroleum emulsions of the water-in-oil type that are commonly referred to as cut oil, roily oil, emulsified oil, etc., and which comprise fine droplets of naturally-occurring waters or brines dispersed in a more or less permanent state throughout the oil which constitutes the continuous phase of the emulsion. This specific application is described and claimed in my co-pending application, Serial No. 226,31 filed May 14, 1951, now U. S. Patent No. 2,626,907.

The new products are useful as wetting, detergent and leveling agents in the laundry, textile and dyeing industries; as wetting agents and spreaders in the application of asphalt in road building and the like; as a flotation reagent in the flotation separation of various aqueous susac-memo for cosmetics, spray oils, water-repellent textile finishes, as lubricants, etc.

For convenience, what is said hereinafter is divided into four parts:

"Part 1 is concerned with the description of the polyhydric reactants employed, as well as reference to other compounds, products, etc.,

a clear line of demarcation between the present invention and What may appear elsewhere;

Part 2 is concerned with the oxypropylated derivatives Part 3 is concerned with the preparation of the acidic esters by reacting the polyhydroxylated compounds with polycarboxy acids; and

Part 4 is concerned valuable derivatives which can be obtained readily from the herein described fractional esters.

PART 1 Generally speaking,

the preparation of organic compounds having approximately the same number of oxygen atoms as carbon atoms are apt to be, and almost invariably are, water-soluble, and the most common could be illustrated by ethyl alcohol, methyl alcohol, acetic acid, acetone, formaldehyde, etc. When compounds reach enormously high molecular weights compared with such simple c0mpounds, for instance, in the category of 30,000

not necessarily guarantee water-solubility as, for example, in the case of cellulose or possibly some There are other classes of comparamolecular weight compounds, for instance, polypentaerythritols, pentaerythritol to deca-pentaerythritol, where the molecular weight varies roughly from 372 to 1,200, which are not water-soluble in the ordinary Pentaerythritol is fairly water-soluble, approximately 4% or 5% in water at ordinary temperature. Di-pentaerythritol is soluble to the extent of two-tenths of one per cent and No. 2,552,528, and 104,802, now abandoned, both filed July 14, 1949. The higher pentaerythritols do not qualify as a raw material in the aforementioned co-pending applications for the reason they do not meet the specification as to Water-solubility prior to oxypropylation.

The present invention, as has been pointed out previously, is concerned with acidic fractional esters which, in turn, are obtained from the oxypropylation products derived from dipentaerythritol and higher polypentaerythritols. Such oxypropylation is conducted to the stage where the end products are xylene-soluble and have a molecular weight within the range of Such polyhydric compounds after oxypropylation are subjected to reaction acids so as to yield acid esters. The acid esters so obtained are valuable for nuand particularly for resolution of water-in-oil emulsions. The oxypropylation derivatives prior to esterification may be considered conveniently as intermediates.

The acidic fractional esters owe their valuable properties, at least in part, to the inherent propwith the use of certain varying from trierties of the parent Ihydroxy compound or the derivatives which have been previouslytreferred to as intermediates. These intermediate compounds herein described owe their peculiar prop- (f) The fact that the initial reactant requires the presence of at least 6 hydroxyl radicals (9) Such combination being obtained by reaction involving propylene oxide.

ning with dipentaerythritol, up to and including the deca-pentaerythritols, or other comparable members of the class. In this connection in Molecular weight Tri-pentaerythritol 372.41 Tetra-pentaerythritol 490.54 Penta-pentaerythritol 608.67 I-Iexa-pentaerythritol 726.80 Hepta-pentaerythritol 844.93 Octa -pentaerythritol 963.06 Nona-pentaerythritol 1,081.19 Deca-pentaerythritol 1,199.32

Other procedures have been described for pre paring polypentaerythritol, using some other catalyst as described in British Patent No. 615,370, to Marrian and McLean (Imperial Chemical Industries, Ltd.)

The same catalyst as used in the above two insoluble, and xylene-insoluble, has at least 6 hydroxyls and a molecular weight not in excess OI" 1200.

Such materials can be varied in an of the final for instance, a mum groups might be converted ketal in the conventional oxypropylated derivative; ber of the hydroxyl into an acetal or a manner; or one might produce an ester of a low molal acid, such as acetic acid, glycollic acid, lactic acid, propionic acid, etc. Tripentaerythritol could be treated with a mole of ethylene oxide or several moles of ethylene oxide, or a mole of glycide, or a mole of 'butylene oxide, or methyl glycide, and then subjected to polymerization so as to give materials which, obviously, are the chemical and also physical-chemical equivalent of the herein specified, preferred and commercially available reactants, i. e., the polypentaerythritols.

My preferred reactants are tripentaerythritol, which is sold commercially, and a higher polyhydroxyl content 32.3). My third preferred reactant is the tetrapentaerythritol manufactured in the manner in Example 2 of aforementioned British Patent No. 615,370.

In a preceding paragraph reference has been made to substantial insolubility in water in certain cases. In examining the data in Part Two of the text it will be noted that the derivatives are limited to those which show xylene-solubility and that in the higher stages of oxypropylation the derivatives show water-insolubility or substantial water-insolubility. This is illustrated by examples and, as a matter of fact, in many instances the water-insoluble derivatives are particularly to be preferred for use as demulsifiern.

PART 2 For a number of well known reasons equipment, whether laboratory size, semi-pilot plant size, pilot plant size, or large scale size, is not as a rule designed for a particular alkylene oxide. Invariably and inevitably, however, or particularly in the case of laboratory equipment and pilot plant size the design is such as to use any of the customarily available allrylene oxides, i. e., ethylene oxide, propylene oxide, butylene oxide, glycide, epichlorohydrin, styrene oxide, etc. In the subsequent description of the equipment it becomes obvious that it is adapted for oxyethylation as well as oxypropylation.

Oxypropylations are conducted under a wide vari ty or" conditions, not only in regard to presence or absence of catalyst, and the kind of catalyst, but also in regard to the time of reaction, temperature of reaction, speed of reaction, pressure during reaction, etc. For instance, oxyalicylations can be conducted at temperatures up to approximately 200 C. with pressures in about the same range up to about 200 pounds per square inch. They can be conducted also at temperatures approximating the boiling point of water or slightly above, as for example 95 to 120 C.

. Under such circumstances the pressure will be less than 30 pounds per square inch unless some special procedure is employed as is sometimes the case, to wit, keeping an atmosphere of inert gas such as nitrogen in the vessel during the reaction. Such low-temperature-low reaction rate oxypropylations have been described very completely in U. S. Patent No. 2,448,664, to H. R. Fife, et al., dated September '7, 1948. Low temperature, low pressure oxypropylations are particlarly desirable where the compound being subjected to oxypropylation contains one, two or three points of reaction only, such as monohydric alcohols, glycols and triols.

Since low pressurelow temperature reaction speed oxypropylations require considerable time, for instance, 1 to '7 days of 24 hours each to complete the reaction they are conducted as a rule described whether on a laboratory scale, pilot plant scale, or large scale, so as to operate automatically. The prior figure of seven days applies especially to large-scale operations. I have used conventional equipment with two added automatic features; (a) a solenoid controlled valve which shuts off the propylene oxide in event that the temperature gets outside a predetermined and set range, for instance, 95 to 120 C., and (1)) another solenoid valve which shuts off the propylene oxide (or for that matter ethylene oxide if it is being used) if the pressure gets beyond a predetermined range, such as 25 to 35 pounds. Otherwise, the equipment is substantially the same as is commonly employed for this purpose where the pressure of reaction is higher, speed of reaction is higher, and time of reaction is much shorter. In such instances such automatic controls are not necessarily used.

Thus, in preparing the various examples I have found it particularly advantageous to use laboratory equipment or pilot plant equipment which is designed to permit continuous oxyalkylation whether it be oxypropylation or oxyethylation. With certain obvious changes the equipment can be used also to permit oxyalkylation involving the use of glycide where no pressure is involved except the vapor pressure of a solvent, if any, which may have been used as a diluent.

As previously pointed out the method of using propylene oxide is the same as ethylene oxide. This point is emphasized only for the reason that the apparatus is so designed and constructed as to use either oxide.

The oxypropylation procedure employed in the preparation of the oxyalkylated derivatives has been uniformly the same, particularly in light of the fact that a continuous automatically-controlled procedure was employed. In this procedure the autoclave was a conventional autoclave made of stainless steel and having a capacity of approximately gallons and a working pressure of one thousand pounds gauge pressure. This pressure obviously is far beyond any requirement as far as propylene oxide goes unless there is a reaction of explosive violence involved due to accident. The autoclave was equipped with the conventional devices and openings, such as the variable-speed stirrer operating at speeds from 50 R. P. M. to 500 R. P. M.; thermometer well and thermocouple for mechanical thermometer; emptying outlet, pressure gauge, manual vent line; charge hole for initial reactants; at least one connection for introducing the alkylene oxide, such as propylene oxide or ethylene oxide, to the bottom of the autoclave; along with suitable devices for both cooling and heating the autoclave, such as a cooling jacket, and, preferably, coils in addition thereto, with the jacket so arranged that it is suitable for heating with steam or cooling with water and further equipped with electrical heating devices. Such autoclaves are, of course, in essence small-scale replicas of the usual conventional autoclave used in oxyal- .kylation procedures. In some instances in exploratory preparations in autoclave having a smaller capacity, for instance, approximately 3 /2 liters in one case and about 1% gallons in another case, was used.

Continuous operation, or substantially continuous operation, was achieved by the use qf a separate container to hold the alkylene oxide being employed, particularly propylene oxide. 75 In conjunction with the smaller autoclaves, the

9 container consists essentially of a laboratory bomb having a capacity of about one-half gallon, or somewhat in excess thereof. In some instances a larger bomb was used, to wit, one having a capacity of about one gallon. This bomb was equipped, also, with an inlet for charging, and an eductor going to the bottom of permit dischargin of alkylene oxide in the liquid phase to the auto- A bomb having pounds was used in connection with the 15- gallon autoclave. Other conventional equipcourse, of the rupture disc, pressure gauge, sight feed glass, thermometer connection for nitrogen for pressuring bomb, etc. The bomb was placed on a scale during use. The connections between the bomb h autoclave were flexible stainless steel hose or tuning so that continuous weighings could be made without breaking or making any connections. plies also to the nitrogen line, which was used to pressure the bomb reservoir. To the extent that it was required, any other protective screens, etc.

Attention is directed again to what has been said previously in regard to automatic controls which shut off the propylene oxide in event temperature of reaction passes out of the predetermined range or if pressure in the autoclave passes out of predetermined range.

maximum point would be at 112 and the lower point would be 95 or possibly 98 the pressure was held at approximately 30 pounds within a -pound the most 110 C. or

ditions as compared with oxyalkylations at 200 C. Numerous reactions were conducted in which the time varied from one day (24 hours) up to three days ('72 hours), for completion of the final member of a series. reaction may take place in time, i. e., 24 h urs or less, as far as a partial oxya capacity of about 60' In some instances the i 10 amples and using 3, 4 or 5 hours instead of 10 hours.

When operating. at. a comparatively high temperature, for instance, between 150 to 200 0., an unreacted alkylene oxide such as propylene oxide, makes its presence felt in the increase in pressure or the consistency of higher pressure.

oxypropylate at a modestly higher temperature, for instance, at to C. Unreacted oxide affects determination of the acetyl or hydroxyl value of the hydroxylated compound obtained.

obtain some of monohydrlc This final stirring period is intended to avoid the presence of unreacted oxide.

In this sort of perature range was controlled automatically by etc., specifically designed for the purpose.

What is said here immediately following is 11 essentially the same data which appeared in my two previously-referred to co-pending applications, Serial Nos. 127,773, now U. S. Patent No. 2,552,533, and 127,774, now abandoned, both filed November 16, 1949. Although I have prepared acidic esters from the compounds described in this subject matter immediately following, yet the polypentaerythritols which are most readily available commercially and, in fact, available from more than one source, are dipentaerythritols and tripentaerythritols. It is my preierence to have a very complete description of the acidic. esters derived from these two latter compounds. Therefore, after this initial presentation identical with what was said in Serial Nos. 127,773, now U. S. Patent No. 2,552,533, and 127,774, now abandoned, I have included extensive data as to these lower monomeric derivatives of pentaerythritol. For purpose of clarity I am designating the older series by Examples 1, 2, 3 etc., and the new series as Examples 1a, 2a,

3a, etc.

Example 1 The reaction vessel employed was a stainless TArlnt. Sglvent Sod 3 en res- Ex. 3:2,: Gms. ent, :5 No. N (801- Gms.

' vent (Xy- Free) lene) A*-Tripentaerythritol. BHeptapentaerythritol. O*--Tetra-pentaerythritol. with the usual devices for heating, heat control, stirrer, inlet, outlet, etc., which are conventional in thistype of apparatus. Two different sizes were employed. In part of the experiments the capacity of the autoclave was 3 /2 liters, and in the other experiments a. -liter capacity autoclave was employed. This was purely a matter of convenience. Otherwise the construction and operation of both autoclaves were the same. In both instances the stirrers operated at a speed of approximately 300 to 350 R. P. M. There were charged into the autoclave 200 grams of tripentaerythritol along with 200 grams of solvent (xylene). Any nonvolatile inert solvent, such as xylene, decalin, diethylether of ethylene glycol, or a higher boiling aromatic be used. Ap-

were added. Sodium methylate was used although ground caustic soda or ground caustic potash or any one of a number of other alkaline catalysts is equally suitable. The autoclave was sealed, swept with nitrogen gas, and stirring started immediately and allowed to rise to approximately 160 C. At this point addition of propylene oxide was started. It was added continuously at such speed that it was absorbed by the reaction as rapidly as added. During this first period approximately 1650 grams of propylene oxide were added. The time resteel autoclave 5 xylene.

ene oxide were added. The

In the case of xylene a temperature of 180 to 200 C. is perfectly satisfactory. The products obtained are usually viscous somewhat sirupy amber, or reddish color.

trace of iron because of contamination from the vessel employed.

employed that contamination by iron there is still discolorato the inherent nature of the initial raw material or a subsequent carmeliza- 12 quired was 3% hours. The maximum tempera: ture was 185 C.

The product obtained still showed dispersibility in water and was not appreciably soluble in Part of the batch was allowed to stay in the autoclave. The exact amount was 790.5 grams. The amount of solvent present was grams. No additional sodium methylate was added. In this second stage 895 grams of propyltime required was 2 hours. The maximum temperature was 173 C., and the maximum pressure pounds per square inch. At the end of the reaction time the ratio of propylene oxide to initial reactant 15 was to 1 as compared to 53 to 1 in the first stage. The product still showed some tendency to disperse in water but was xylene-soluble.

The further addition of propylene oxidewas made in subsequent stages until the product was 20 practically insoluble in water. The data are recorded in the following table. It is to be noted that additionally two other polypentaerythritols were treated with propylene oxide and data included in the table, also.

Solubility in Water l Dispersible l Tendency to Yes.

disprs. :1 Less disprs :l Almost insoL l Disprs 1 Almost disprs D Almost disprs. Almost insol The products obtained above, of course, conwit, xylene in this particular The solvent can be removed in the distillation. C.

tain a solvent, to instance. conventional manner by vacuum liquids of an amber, dark The color may be due to a However, even when stainless-steel is of such character seems out of the question, tion, probably due tion-like reaction.

The derivatives 50 obtained can be decolorized in the usual manner by treating with charcoal, or the like. If the solvent is to to be decolorized, or else there may be some decolorization due to However, for such materials necessity for decolorizing as in the present instance,

filtering clay, 65 be removed and the product has the heat used in solvent removal. the bulk of purposes for which are used there is no and in many instances,

the solvent may remain in the material.

It will be noted that the molecular weight range of the acceptable final products is within Experimentation 75 with polypentaerythritols higher than heptathe ratio Of 5,000 to 65,000.

pentaerythritol has resulted in compounds which appear to be in the approximate weight range of 50,000 to 60,000. This figure cannot be set exactlyfor the reason that the exact composition of the higher polypentaerythritols is not exactly known. An attempt was made in this case' to produce a deca-pentaerythritol and the composition -l ey vary somewhat from the theoretical formula. For this reason, in the claims 65,000 was set as the upper limit.

It is obvious that ility goes, are xyleneay, the initial material Similarly,

after oxypropylation starts one could interrupt th variation parting the slightest from the spirit of the invention.

ne examines the that starting wit If 0 previous table it will be noted h a ra Stated another Way, w material may contribute as little as 1% to the final nge is approximately 7%,

of the final product.

As pointed out previously the next series of intermediates will be described as Examples 1a through 13a, inclusive. These are the intermediates which are used in preparing the acidic esters described in Part 3 immediately following.

The equipment, procedure, etc, were the same as have been previous series. some comed at modestly above the boilabout 240 to 250 F. Note that in the first series the temperature is recorded in degrees centigrade whereas in the instant series it is recorded in degrees Fahrenheit.

Example 111 aterial emplo pounds being prepar ing point of water,

The starting in cial dipentaerythritol. was caustic soda. The one having a capacity 0 proximate] yed was commer- The catalyst employed autoclave employed was i about 15 gallons or apfollowing.

pounds 'o f pr'o pylene cease. The injection id or l1 po ple 2a pc-itifids of e r q mass equivl fif in Ex in regard to temperature and pressur ti-onal catalyst Was introduced. The reaction time was 4 hours. The amount of oxide mam due-ed was 21.5 pounds. This was introduced at the rate of about 7 pounds per hour. pletion. of the r Withdrawn as a ,iected to furthe the next su particularly e. N o addi r oxypropylation as described in ccee'ding exam Examzflle 3a the reaction mass previously 50.63 pounds, of

ple and equivalent to 4.62

ZllSl-iC soda, and cted to further be manner described in the eding examples. In this howoxypro'pylation in t as pre'c uired to add it was 4 hours; was about 6 or 7 pounds er oxypropy ediately foll 15 3.63 pounds of solvent, were subjected to further oxypropylation as previously noted. 18.25 pounds of propylene oxide were added in a -hour period at a rate of about 4 to 5 pounds per hour. At the end of the reaction part of the sample was withdrawn and the remainder subjected to further oxypropylation as noted in Example 50., following.

Eacample 5a 50.13 pounds of reaction mass previously identified as Example 4a and equivalent to 2.48 pounds of dipentaerythritol, 46.7 pounds of propylene oxide, and .24 pound of caustic soda and 2.71 pounds of solvent, were subjected to further oxypropylation in previously described. The amount of propylene oxide added was 21 pounds. It was added in a 7-hour period at the rate of about 3 pounds per hour. At the completion of the reaction part of the sample was withdrawn and the remainder subjected to a final oxypropylation as described in Example 6a, immediately following.

Example 6a 53.76 pounds of reaction mass previously idenfled as Example 5a, and equivalent to 1.82 pounds of dipentaerythritol, 49.77 pounds of propylene oxide, .18 pound of caustic soda, and 1.99 pounds or solvent, were subjected to oxypropylation with time required was 7 hours and proximately 2 pounds per hour.

The series of examples, 7a through 13a, is comparable to previous series, Examples 1a through 6a, except that the initial material is tripentaerythritol instead of dipentaerythritol. The procedure is obviously comparable to that used in Examples 1a through 6a, and also conforms to what has been said previously.

Example 7a the rate was ap- The initial charge was 7.5 pounds of tripentaerythritol along with 17 pounds of xylene as a solvent, and .75 pound of caustic soda. The amount of propylene oxide added was 19.75 pounds. about 10 to 12 pounds per hour. A comparatively higher temperature was noted in this particular oxypropylation, to wit, 300 to 320 F. (not centigrade). The pressure devices were set for a maximum of 3537 pounds per square inch. Subsequently both the temperature and pressure were lower. Since the initial reactant was not soluble in xylene there was some tendency for the reaction to be sluggish until it was at least partially soluble in xylene or completely solube in As soon as the reaction was complete part of the sample was withdrawn and subjected to further oxypropylation as described in Example 8a, immediately following.

Example 80.

37.88 pounds of reaction mass previously iden-. tified as Example 7a, and equivalent to 6.32 pounds of tripentaerythritol 16.63 pounds of propylene oxide, .63 pound of catalyst, and 14.3 pounds of xylene were subjected to further oxypropylation in the same manner as previously described. The amount of propylene oxide was 22.25 pounds. It was added in a 3-hour period at a rate of about 8 or 9 pounds per hour. No additional catalyst was added. This applies also to Examples 9a, through 13a, following.

In this example the maximum was 250-270 F. This applies also 9a through 13a,

temperature to Examples following. The pressure con- 12.5 pounds of propylene oxide. The

The addition was made at the rate of Example 9a 48.11 pounds of reaction mass previously identified as Example 8a, and equivalent to 5.06 pounds of tripentaerythritol, 31.13 pounds of propylene oxide, .5 pound of caustic soda and 11.42 pounds of solvent, were subjected to further oxypropylation with 43.77 pounds of propylene oxide. This oxide was added in 6 hours at the rate of about 9 pounds per hour. At the end of the reaction part of the reaction mass was withdrawn and the remainder subjected to oxypropylation as described in Example 10a, following.

Emample 10a 49 pounds of reaction mass identified as EX- ample 9a, preceding, and equivalent to 2.7 pounds of tripentaerythritol, 39.93 pounds of propylene oxide, .27 pound of caustic soda, and 6.16 pounds of solvent, were subjected to further oxypropylation in the manner previously described. The amount of oxide added was 15.5 pounds of propylene oxide. The oxide was added in a 3-hour period at the rate of about 6 pounds per hour. t the end of t 1e reaction part of the reaction mass was withdrawn and the remainder subjected to further oxypropylation as described in Example 11a, immediately following.

Example 11a 56.51 pounds of reaction mass identified as Example 10a preceding and equivalent to 2.36 pounds of tripentaerythritol, 48.56 pounds of propylene oxide, .23 pound of caustic soda, and 5.36 pounds of solvent, were subjected to further oxypropylation in the manner previously described. The amount of oxide added was 10.5 pounds. It was added in a 23-hour period at the rate of about 5 pounds per hour. At the end of the reaction, part of the sample was withdrawn and the remainder subjected to further oxypropylation in the manner described in the next example.

Example 12a 59 pounds of the reaction mass identified as Example 11a, preceding, and equivalent to 2.08 pounds of tripentaerythritol, 52 pounds of propylene oxide, .2 pound of catalyst and 4.72 pounds of xylene were subjected to further oxypropylation. The amount of propylene oxide was 18 pounds andreaction time was 4 hours. The rate of oxide addition was about 5 pounds per hour. At the completion of the reaction part of the reaction mass was withdrawn and the remainder subjected to final oxypropylation as described in Example 13a, following.

Example 13a 56.5 pounds of reaction mass identified as EX- ample 12a, preceding, and equivalent to 1.52 pounds of tripentaerythritol, 51.37 pounds of propylene oxide, .15 pound of caustic soda, and 3.46 pounds of xylene, were reacted with 12.25 pounds of propylene oxide in a 5 hour period. The addition of the oxide was at the rate of about 3 pounds per hour.

What has been said preceding is presented in tabular form in Table 1, following, with some added information as to molecular weight and as and requires noiurther elaboration. In fact, it to solubility of the reaction product in water, is illustrated by some of the examples appearing xylene, and kerosene. in the patent previously mentioned.

TABLE 1 Composition Before Composition at End Max Max.

' Pres., Time. 2. 231 15 9;? 3:117:55 Theo ii. 2x135 c352- Solvent Hyd. fi lbs. hrs.

111., m m 111., 111., ,st, M01. s lbs. lbs g lb lbs. lbs. lbs. Wt, q m 7.75 .75 3.50 1575 7.75 43. 50 .75 3. 50 1352 220-230 35-37 5 5. 75 37. 35 55 7. 33 2430 5. 75 59. 35 55 7. 33 1003 220-230 35-37 4 4. 52 40. 51 45 5. 05 3554 4. 52 51. 75 45 5. 05 2553 240-250 20-25 4 3.32 44.35 .33 3.53 5040 3.32 52.50 .33 3.53 3492 240-250 20-25 5 2. 43 45. 70 .24 2. 71 7100 2. 43 57. 70 .24 2. 71 4335 240-250 20-25 7 1. 32 49. 77 .13 1. 99 3940 1. 32 52. 27 13 1. 4550 240-250 20-25 7 7.5 .75 17.0 1350 7.5 19.75 .75 17.0 300-320 3a37 2% 5. 32 15. 53 53 14. 3 2750 5. 32 33. 33 .53 14. 3 1952 250-270 15-20 3 5. 31. 13 50 11. 42 5370 5. 05 74. 90 50 11.42 3592 250-270 15-20 5 2. 70 39. 93 .27 5. 3010 2. 70 55. 43 27 5. 10 4545 250-270 -20 3 2. 35 43. 55 .23 5. 35 9530 2. 35 59. 05 23 5. 35 5240 250-270 1 3 2. 03 52. 00 .20 4. 72 12370 2. 03 70. 00 4. 72 5123 250-270 15-20 4 1.52 51.37 .15 3.45 15930 1. 52 53.52 .15 3. 45 5200 250-270 15-20 5% I In Examples 1a through 6a the hydroxy com- PART 3 pound was dipentaerythritol In Examples 741 through 1305 the hydroxy compound was tri- As previously pointed out the present invention pentaerythritol. 5 is concerned with acidic esters obtained from the 50 and 6a were insoluble in water, soluble in r yd d u e a diglycollic acid, xylene, and also soluble in kerosene, sebacic acid, azelaic acid, aconitic acid, maleic Examples 7a and 8a were insoluble in water, acid or anhydride, citraconic acid or anhydride, Xylene, or kerosene; Examples 9a, 1041, and 11a maleic acid or anhydride adducts as obtained by in both xylene and kerosene. composed during esterification. They may con- I'he final products varied from a light straw tain as many as 36 carbon atoms as, for example, color thru pale amber, to somewhat viscous fluids the acids obtained by dimerization of unsaturated of a rather dark a b r olor in ne or tw in fatty acids, unsaturated monocarboxy fatty acids, stances. This was more or less the characterr un ur ed m n r y a i hav n 18 ristic of all the oxypropylated products at the bOIl atoms. Reference to the acid in the hereto various stages. These products were, of course, appended claims Obviously ud t yslightly alkaline due to the residual caustic soda. drides or any other obvious equivalents. The residual basicity, due to the catalyst, of 5 r f r n how ver, i o u p ly rb xy acids course, would be the same as if sodium methylate vin not over 8 carbon atoms. had been sed, The production of esters including acid esters Speaking of insolubility in water 01' solubility i al t s) f m p ly a y ds and in kerosene such solubility test can be made glycols or other hydroxylated compounds is well simply by shaking small amounts of the maknown. Needless to say, various compounds may terials in a test tube with water, for instance, be used such as the low molal ester, the anhydride, using 1% to 5% approximately based on the the acyl chloride, etc. However, for purpose of amount of water present. economy it is customary to use either the acid Needless to say, there is no complete converor the anhydride. A conventional procedure is sion of propylene oxide into the desired hydroxylated compounds. This is indicated by a resin pot of the kind described in U. S. Patent the fact that the theoretical molecular Weight No. 2,499,370, dated March 7, 1950 to De Groote value. This matter has been discussed in the ionic acid and that is that at the end of the reacliterature and is a matter of common knowledge 7 tion it can be removed by flushing out with nitrogen, whereas there is no reasonably convenient means available of removing the paratoluene sulfonic acid or other sulfonic acid employed If hydrochloric acid is employed one need only pass the gas through at an exceedingly slow rate so as to keep the reaction mass acidic. Only a trace of acid need be present. I have employed hydrochloric acid gas or the aqueous acid itself to eliminate the initial basic material. My preference, however, is to use no catalyst whatsoever.

The products obtained in Part 2 preceding may contain a basic catalyst. As a general procedure I have added an amount of half-concentrated hydrochloric acid considerably in excess of what is required to neutralize the residual catalyst. The mixture is shaken thoroughly and allowed to stand overnight. It is then filtered and refiuxed with the xylene present until the water can be separated in a phase-separating trap. As soon as the product is substantially free from water the distillation stops. This preliminary step can be carried out in the flask to be used for esterification. If there is any further deposition of sodium chloride during the reflux stage needless to say a second filtration may be required. In any event the neutral or slightly acidic solution of the oxypropylated derivatives described in Part 2 is then diluted further with sumcient xylene, decalin, petroleum solvent, or the like, so that one has obtained approximately a 40% solution. To this solution there is added a polycarboxylated reactant as previously described, such as phthalic anhydride, succinic acid or anhydride, diglycollic acid, etc. The mixture is refluxed until esterification is complete as indicated by elimination of water or drop in carboxyl value. Needless to say, if one produces a half-ester from an anhydride such as phthalic water is eliminated. However, if it is obtained from diglycollic acid, for example, water is eliminated. All such procedures were conventional and have been so thoroughly described in the literature that further consideration will be limited to a few examples and a comprehensive table.

Other procedures for eliminating the basic residual catalyst, if any, can be employed. For example, the oxyalkylation can be conducted in absence of a solvent or the solvent removed after oxypropylation. Such oxypropylation end product can then be acidified with just enough concentrated hydrochloric acid to just neutralize the residual basic catalyst. To this product one can then add a small amount of anhydrous sodium sulfate (sufficient in quantity to take up any water that is present) and then subject the mass to centrifugal force so as to eliminate the hydrated sodium sulfate and probably the sodium chloride formed. The clear somewhat viscous straw-colored or amber liquid so obtained may contain a small amount of sodium sulfate or sodium chloride but, in any event, is perfectly acceptable for esterification in the manner described.

It is to be pointed out that the products here described are not polyesters in the sense that there is a plurality of both polypentaerythritol radicals and acid radicals; the product is characterized by having only one polypentaerythritol radical.

By following slight modifications of what has been said previously one can conduct the esterification on a laboratory scale with greater convenience. Obviously, if one starts with a polyhydric compound having 3' or more hydroxyls and adds a dicarboxy acid there is at least some opportunity for cross-linking and formation of insoluble materials. However, insolubility or a gelation effect can arise in other ways, for instance, possible incipient cross-linking rather than intermediate or complete cross-linking, and also the fact that there are certain limitations as far as solubility goes in say nothing of peculiarities of structure insofar that one of the original reactants, for instance, dipentaerythritcl or tripentaerythritol, are much less soluble in water than one might ordinaritly expect on the carbon-oxygen ratio. After the water is removed in the case of the esterification by means of a water-insoluble solvent, such as benzene, xylene or the use of some other comparable solvent or mixtures, one is confronted with the fact that the acidic ester is not necessarily soluble in such nonpolar solvent, and possibly because it either does cross-link or at least gives a pseudo gel. I have used the terminology pseudo gel for the reason that such gel is reversible as distinguished from a true non-reversible gel produced by cross-linking. The exact nature of this tendency to become insoluble toward gelation is obscure and not fully understood. In light of the effect of semipolar solvents there may be some relationship, and in fact an important one to hydrogen bonding factors.

However, by the addition of a semi-polar solvent, such as diethyl Carbitol, which is the trade name for diethyleneglycol diethylether, or some other similar solvent such as an alcohol, one tends. to reduce or eliminate this effect. The alcohol, of course, must be added at the end of the reaction so as to not interfere with the esterification. The non-hydroxy semi-polar solvent :can be obtained at the start of esterification provided it does not interfere with water removal. In any event, one can obtain a homogeneous system in. which substantially the entire material is solid.

Referring to the original oxypropylation it is to be noted that a solvent, such as xylene, is present for a matter of convenience such as giving an incipient slurry. Also, it is to be noted that: the intermediates are xylene-soluble especially in the latter stages. Therefore, even if one were to use benzene alone or cymene alone, there still would be present the xylene which had been used Referring now to a number of examples, for instance, Examples 112 through 36b, the solvent is indicated as benzene, xylene, diethyl Carbitol. Diethyl Carbitoi is, as previously pointed out, the diethyl ether of diethylene glycol. The xylene indicated is not added xylene but refers. to the xylene used in the oxypropylation step. In each instance the amount of benzene added was 50 grams. Then sufficient diethyl Carbitol was added to give the indicated weight. Actually, the amount of this latter solvent added was judged purely as a matter of convenience in the glassware employed, and when the reaction was complete the reaction mass was Weighed, and this weight used to calculate the actual total solvent. In each instance an effort was made to obtain approximately a 50% solution. For instance, in Example it the amount of hydroxylated ma terial, 109 grams, was on a solvent-free basis. The amount of total solvents added, 200.7 grams, included the xylene which originally accompanied the hydroxylated material. In every in-- stance an effort was made to obtain a homogene one solution even if there happened to be presany large molecule, to

out more than 50% of solvent. The selection of 50% solvent was just arbitrary for the reason that when these compounds were tested for demulsification it was convenient to have a 50% solution. It goes without saying that a 25% solution would serve also. In practically every instance after a homogeneous solution was obtained one could subject it to distillation, parsolution having exactly 50% if desired. In this modification one could, of course, use decalin, cymene, or some other ether such as the diethyl ether of ethyleneglycol, or a comparable ether instead of the particular one used.

What has been said previously applies also to some of the other derivatives although some other variants can be employed for instance,

in Examples 40b and 4.16 there was a tendency for solids to separate out. In these experiments there was some solid material at the end of the procedure which apparently was soluble in methanol. Therefore, a small amount of methanol, approximately 10 to hereto attached claims.

The data included in the subsequent tables, i. e., Tables 2 and 3, are self-explanatory, and very complete, and it is believed no further elaboration is necessary.

' TABLE 2 Wt. Amt. of g gi gg'gi Polycarhoxy Reactant ca'rboxy Actual (grs) Reactant v (E 201 64.3 201 60.5 201 83.5 201 71.0 1 1, 362 10s. 9 47. 0 1 1, 362 10s. 9 70. 0 136 176. 5 1, 90s 95. 4 2 136 176.5 1,908 95.4 37.8 136 176. 5 1, s 95. 4 52 2 136 176. 5 1, 908 95. 4 44 4 136 176.5 1,908 95.4 29 4 136 176. 5 1, 908 95.4 Adipic Acid..-.. 43. 8 94. 5 127 2, 658 106.3 Diglycolic Acid. 32. 2 04. 5 127 2, 658 106. 3 Oxalic Acid 30. 3 94. 5 127 2, 658 106. 3 Aconitic Acid 41. 8 94. 5 127 2, 658 106. 3 Adipic Acid 35. 0 94. 5 1.27 2, 658 106. 3 Phthalic Anhyd. 35. 5 94. 5 127 2, 658 106. 3 Maleic Anhyd- 23. 5 67. 0 96. 5 3, 492 104. 8 Diglycolic Acid. 24. 0 67. 0 96. 5 3, 492 52. 4 Oxalic Acid. l1. 3 67. 0 96. 5 3, 492 139. 4 Aconitic Acid-- 41. 8 67. 0 96. 5 3, 492 139. 7 Adipic Acid-- 35. 0 67.0 96. 5 3, 492 139. 7 Phthalic Anhyd- 35. 5 67. 0 96. 5 3, 492 104. 8 Maleic Anhyd. l7. 6 47. 0 69. 7 4, 836 96. 7 Diglycolic Acid 16.1 47.0 69. 7 4, 836 96. 7 Oxalic Acid..-.. 18.1 47. 0 69. 7 4, 836 96. 7 Aconitic Acid 20.9 47. 0 69. 7 4, 836 96. 7 Adipic Acid 17.5 47. 0 69. 7 4, 836 96. 7 Phthalic Anhyd.. 17.8 47. 0 69. 7 4, 836 96. 7 NIaleic Annhyd.- 11.8 37.7 73.7 4, 560 91.2 Diglycolic Acid- 16.1 37. 7 73. 7 4, 560 91.2 Oxalic Acid... 18.1 37. 7 73. 7 4, 560 91. 2 Aconitic Acid. 20.9 37. 7 73. 7 4, 560 91. 2 Adipic Acid--. 17.5 37. 7 73. 7 4, 560 91. 2 Phthalic Anhyd 17.8 37.7 73.7 4, 560 91.2 Maleic Anhyd.. 11.8 163. 5 230 1, 952 97. 6 Diglycolic Acid. 53.6 163. 5 230 l, 952 97. 6 Oxalic Acid--. 50.4 163. 5 230 1, 952 97. 6 Aconitic Acid. 69.6 163. 5 230 1, 952 97. 6 Adipic Ac1d.. 58.4 163. 5 230 1, 952 97. 6 Phthalic Anhyd- 59.2 163. 5 230 1, 952 97. 6 Bialeic Anhyd.-. 39.2 76. 5 125. 0 3, 592 107. 8 Diglycolic Acid.. 32.2 76. 5 3, 592 107. 8 Oxalic Acid..-. 30.6 76. 5 3, 592 107.8 Aconitic Ac1d.. 41.8 76. 5 12 3, 592 107. 8 Adlpic Acid.- 35.0 76. 5 3, 592 107. 8 Phthalic Anhyd- 35.5 76. 5 125. 0 3, 592 107. 8 Maleic Anhyd--. 23.5 56. 0 96. 9 4, 640 92. 8 Diglycollc Acid 21.5 56. 0 96. 9 4, 640 92. 8 Oxalic Acid---.. 20.2 56.0 96. 9 4, 610 92. 8 Acouitic Ac1d.. 27.8 56. 0 96. 9 4, 640 92. 8 Adipic Acid 23.4 56.0 96. 9 4, 6-10 92. 8 Phthalic Anhyd. 23.7 56. 0 96. 9 4, 640 92. 8 Maleic Anhyd.- 17.5 46. 4 86. 0' 5, 210 104. 8 Diglycolic Acid- 21.5 46. 4 86. O 5, 210 104. 8 Oxalic Acid.-. 20.2 46. 4 86. 0 5, 240 104. 8 Aconitic Acid 27.8 46.4 86.0 5,240 104.8 23.4 46.4 86.0 5,240 104.8 23.7 46.4 86.0 5,210 104.8 15.7 34. 9 73. 4 6, 128 122. 6 iglycolic Acid 21.5 34. 9 73. 4 6, 128 122. 6 OXalic Acid--. 20.2 34. 9 73. 4 6, 128 122. 6 Aconitic Acid- 27.8 34. 0 73. 4 6, 128 122. 6 Adipic Acid-. 23.4 34. 9 73. 4 6, 128 122. 6 Phthalic Anhyd- 23.7 34. 9 73. 4 6, 128 122. 6 Malelc Anhyd--. 15.7 28. 1 72. 4 6, 200 124 Diglycolic Ac1d-. 21.5 28. l 72. 4 6, 200 124 Oxalic Acid.. 20.2 28. 1 72. 4 6, 200 124 Aconltic Acid. 27.8 28. 1 72. 4 6, 200 124 Adipic Acid--. 23.4 28. 1 72. 4 6, 200 124 Phthalic Anhyd 23.7 28. 1 72. 4 6, 200 124 Maleic Anhycl- 15.7

TABLE 3 1 1 1 Water Percent Acid Solvent Ester 1b.... Benzene, Xylene, 200.7 55 2b Difthylcarbitol.

. 2 14% 11% .8 3% .2 1 .3 1 .3 1% 5.0 3% 8.5 3 126.4 1 112.9 =4 107.6 118.1 111.7 51 117.5 2% 51 110.0 *4 51 107.9 A 51 102.5 54 7.0 51 112.3 =4 3.2 51 109.9 A 2.2 1 .0 A 0.6 51 .7 y, 0.5 51 .3 1 7.2 59 1. 21. 6- 59 1%, 7.2 8 2% 7.2 58 1 1.0 58 1 1.0 59 M 4.6 55 1% 13.0 55 i 4.6 54 3 4.4 2:

3.0 50 8.6 50 3.0 50 d0" 3.0 50 Benzene, Xylene, 0. 8 50 Diethylcarbitol, Methanol. 60b Benzene, Xylene, 119.7 0.8 50

Diethylcarbitol.

for

The procedure has been illustrated by preceding examples.

seeaaeaaaeaaaeseeaeeeaaa some other acid as a catalyst; (11) if the esterification does not produce a clear product a check should be made to see if an inorganic salt such as sodium chloride or sodium sulfate is not precipitating out. Such salt should be eliminated, at least for exploration experimentation, and can be removed by filtering. Everything else being equal, as the size of the molecule increases and the reactive hydroxyl radical represents a smaller fraction of the entire molecule more difficulty is involved in obtaining complete esterification.

Even under the most carefully controlled cond-itions of oxypropylation involving comparatively low temperatures and long time of reaction there are formed certain compounds whose compositions is still obscure. Such side reaction products can contribute a substantial propor tion of the final cogeneric reaction mixture. Various suggestions have been made as to the nature of these compounds, such as being cyclic polymers of propylene oxide, dehydration products with the appearance of a vinyl radical, or isomers of propylene oxide or derivatives thereof, i. e., of an aldehyde, ketone, or allyl alcohol. In some instances an attempt to react the stoichiometric amount of a polycarboxy acid with the oxypropylated derivative results in an excess of the carboxylated reactant for the reason that apparently under conditions of reaction less reactive hydroxyl radicals are present than indicated by the hydroxyl value. Under such circumstances there is simply a residue of the carboxylic reactant which can be removed by filtration or, if desired, the esteriiication procedure can be repeated using an appropriately reduced ratio of carboxylic reactant.

Even the determination of the hydroxyl value and conventional procedure leaves much to be desired due either to the cogeneric materials previously referred to, or for that matter, the presence of any inorganic salts or propylene oxide. Obviously this oxide should be eliminated.

lhe solvent employed, if any, can be removed from the finished ester by distillation and particularly vacuum distillation. The final products or liquids are generally straw or pale amber through dark amber in color, and some have a distinct yellowish cast and show moderate viscosity, or sometimes increased viscosity in light of what has been said previously in regard to cross-linking, gelation, etc. Unless there is some reason to do otherwise my preference is to handle these esters as 50% solutions in suitable solvents. lhey can be bleached with bleaching clays, filtering chars, and the like. However, for the purpose of demulsification or the like color is not a factor and decolorization is not justified.

PART 4 As pointed out previously the final product obtained is a fractional ester having free carboxyl radicals. Such product can be used as an intermediate {or conversion into other derivatives which are effective for various purposes, such as the breaking of petroleum emulsions of the kind herein described. For instance, such product can be neutralized with an amine so as to increase its water solubility, such as triethanolainine, tripropanolamine, oxyethylated triethanolamine, etc. Similarly, such product can be neutralized with some amine which tends to reduce the water-solubility such as cyclohexylespecially in demulsification of water-in-oil emulsions.

Having thus described my invention what I claim as new and desire to secure by Letters Patent, is

1. An ester of a 2'6 on a statistical basis and the assumption of complete reaction involving the propylene oxide and polypentaterythritol and in which the polyhydrogen and oxygen.

2. A product as in claim 1 wherein the polypentaerythritol has at least 2 and not more than 3 erythritol radicals.

3. The product of claim 2 wherein the polycarboxy acid is a dicarboxy acid.

4. The product of claim 3 wherein the dicarboxy acid is phthalic acid.

5. The product of claim 3 wherein the dicarboxy acid is maleic acid.

6. The product of claim 3 wherein the dicarboxy acid is succinic acid.

7. The product of claim 3 wherein the dicarboxy acid is citraconic acid.

8. The product of claim 3 wherein the dicarboxy acid is diglycollic acid.

N 0 references cited. 

1. AN ESTER OF A POLYCARBOXY ACID AND AN OXYPROPYLATED POLYPENTAERYTHRITOL IN WHICH THE RATIO OF POLYCARBOXY ACID TO OXYPROPYLATED POLYPENTAERYTHRITOL IS ONE MOLE OF THE ACID FOR EACH AVAILABLE HYDROXYL RADICAL OF THE OXYPROPYLATED POLYPENTAERYTHRITOL AND IN WHICH THE OXYPROPYLATED POLYPENTAERYTHRITOL HAS A MOLECULAR WEIGHT BETWEEN 5.000 AND 65,000 AND THE POLYPENTAERYTHRITOL REPRESENTS NOT MORE THAN 7% BY WEIGHT OF THE OXYPROPYLATED POLYPENTAERYTHRITOL ON A STATISTICAL BASIS AND THE ASSUMTPITON OF COMPLETE REACTION INVOLYING THE PROPYLENE OXIDE AND THE POLYPENTAERYTHRITOL AND IN WHICH THE POLYCARBOXY ACID IS SELECTED FROM THE GROUP CONSISTING OF ACYCLIC AND ISOCYCLIC POLYCARBOXY ACIDS HAVING NOT MORE THAN 3 CARBOXY GROUPS NOR MORE THAN 8 CARBON ATOMS AND COMPOSE OF CARBON, HYDROGEN AND OXYGEN. 